This application is based upon and claims the benefit of priority from the prior Japanese Patent Applications No. 2001-87719, filed Mar. 26, 2001; and No. 2001-349211, filed Nov. 14, 2001, the entire contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to an optical path switching apparatus used in the field of optical communication or optical connection.
2. Description of the Related Art
Switching of a transmission path of optical signals is an important technique in the field of optical communication or optical connection. Such optical path switching is utilized in, e.g., an optical switch, which selects an optical signal from a plurality of transmission paths and switches it to a new path, and an optical monitor, which monitors the statuses of each path. A mechanical optical switch that changes over an optical path by mutually moving opposed optical fiber end faces is simple in structure and has advantages of low insertion loss and small size. Many mechanical optical switches have been proposed.
For example, Jpn. Pat. Appln. KOKAI Publication No. 295623/1999 discloses a pressing mechanism, which moves an optical fiber on a light reception side along an arrangement of a plurality of optical fibers on a transmission side, carries out positioning and then presses the optical fiber end surfaces against each other in order to suppress losses. Movement and pressing are conducted by an ultrasonic linear motor, and the stop position of the optical fiber on the light reception side is controlled by a computer.
Further, Jpn. Pat. Appln. KOKAI Publication No. 72398/1995 or 160633/1999 discloses an apparatus, which fixes a plurality of optical fibers in V-shaped grooves in advance and changes over the optical path by moving the optical fiber opposed to the fixed fibers between the V-shaped grooves by a drive mechanism. In the apparatus, the position accuracy after changeover is improved by fixing the optical fibers in the V-shaped grooves (grooves having the V-shaped cross section).
Furthermore, Jpn. Pat. Appln. KOKAI Publication No. 50253/1996 proposes an optical switch, which includes a plurality of optical fibers arranged on the surface of a circular cylinder, which is rotated by a step motor so that one of the optical fibers is coupled an opposed optical fiber.
In the mechanical optical switch, which distributes signals from a plurality of optical fibers, the optical fibers on the transmission and reception sides must be optically coupled with each other with the low coupling loss. That is, there is required a mechanism that brings the optical axes of the optical fibers on the transmission and reception sides into line after the changeover operation. In order to match the optical axes with each other with the high accuracy, a fixing jig having a V-shaped groove structure or a positioning marker is generally used as described above.
The combination of these members with the drive mechanism that carries out mechanical movement complicates the structure of the apparatus. Moreover, the complicated structure easily comes under the influence of fluctuations in environment, and its characteristic is hard to be kept constant for a long period of time. In order to improve the problem, for example, a mechanism that presses the optical fiber end surfaces against each other is added, but this further complicates the structure of the apparatus.
In addition, in the optical switch having the structure using the V-shaped grooves, since the optical fiber is once lifted from the groove and moved at the time of changeover, high-speed switching is difficult. The operation for pressing the end faces against each other after movement is not suitable for high-speed switching either.
An object of the present invention is to provide an optical path switching apparatus that can perform high-speed switching and whose characteristic is stable with respect to fluctuations in environment.
According to an aspect of the present invention, there is provided an optical path switching apparatus, which includes an optical element array having a plurality of the first optical elements, for optically coupling one of the first optical elements with a second optical element, the optical path switching apparatus comprising: a guide extending substantially parallel to an alignment of the first optical elements; a movement mechanism for moving the second optical element, the movement mechanism including a movement portion capable of moving along the guide, the movement portion supporting the second optical element; and position detecting means for detecting a position of the second optical element. The optical path switching apparatus preferably further comprises a control portion for controlling the position of the movement portion based on information obtained by the position detecting means.
According to another aspect of the present invention, there is provided an optical path switching apparatus, which includes an optical element array having a plurality of the first optical elements, for optically coupling one of the first optical elements with a second optical element, the optical path switching apparatus comprising: a deflecting mirror for deflecting an optical path between the first optical element and the second optical element; a guide extending substantially parallel to an alignment of the first optical elements; a movement mechanism for moving the deflecting mirror, the movement mechanism including a movement portion capable of moving along the guide, the movement portion supporting the deflecting mirror; and position detecting means for detecting a position of the deflecting mirror. The optical path switching apparatus preferably further comprises a control portion for controlling a position of the movement portion based on information obtained by the position detecting means.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.